Unconventional Spin Currents in Noncollinear Antiferromagnet Mn<sub>3</sub>Ge.

Cao, Cuimei; Chen, Shiwei; Xie, Nian; Chen, Jinsen; Guo, Zhe; Zhang, Hui; Li, Zheng; Wang, Yihan et al. · Nano Lett · 2025

basic_science · Level V

Where this comes from

Abstract

Unconventional spin-orbit torque (SOT) has garnered significant attention due to its potential for enabling energy-efficient and deterministic control of magnetization states. Noncollinear antiferromagnets (NCAFs) are considered ideal systems for generating such unconventional SOTs, making them highly promising for the development of next-generation spintronic devices. In this study, we report the generation of spin torques in noncollinear antiferromagnetic Mn<sub>3</sub>Ge, revealing the presence of unconventional spin polarizations (specifically, <i>x</i>- and <i>z</i>-polarized spin currents) by employing the spin-torque ferromagnetic resonance (ST-FMR) technique. All-electric SOT switching was successfully demonstrated in a Mn<sub>3</sub>Ge-based device with perpendicular magnetic anisotropy (PMA), with a critical current density of 4.2 × 10<sup>6</sup> A/cm<sup>2</sup>. Furthermore, the device exhibits memristive behavior that effectively emulates the functionality of artificial synapses in convolutional neural networks (CNNs), achieving an accuracy of 92.5% in digital recognition tasks. These results are expected to pave the way toward next-generation fast and energy-efficient memory and neuromorphic computing.